Correlations between pathogen concentration and fecal indicator marker genes in beach environments

The concentrations of several potential pathogens were measured using a microfluidic quantitative PCR (MFQPCR) platform in beach water, sand, and sediment samples collected in Duluth, MN. Among the 19 pathogen marker genes examined, eaeA from Escherichia coli and plc from Clostridium perfringens were most frequently detected in all samples. In beach water and wastewater samples, positive correlations were observed between quantities of potential pathogens and most of the fecal indicator genetic markers. Such correlations, however, were not frequently observed in sand and sediment samples. Our results suggest that the behavior of potential pathogens and FIB may vary by sample type and source of contamination. Consequently, appropriate FIB marker genes need to be chosen for reliable water/sand quality monitoring.